Knockdown crane boom



Nov. 4, 1941. R. G. LE TOURNEAU 7 2,251,473

' KNOCKDOWN CRANE BOOM Filed June 5, 1940 2 Sheets-Sheet l NVENTOR s r W1 ATTORNEYS the cables 'removed.

Patented Nov. 4, 1941 UNITED STATES. PATENT OFFICE KNOCKDOWN CRANE BOOM Robert Gilmore Tourneau, Peoria, 111., assignor to R. G. Le Tournean, Inc., a corporation of California Application June 5, 1940. Serial No. 338,941 In Brazil May 8, 1940 '(Cl. 21H) 4 Claims.

tered.

It is therefore the principal object of themesent invention to avoid these difficulties by constructing the boom of a number of separate parts with means to easily and quickly connect these a parts together in a detachable manner, and so: that the boom when completely assembled, will have adequate strength and rigidity, coupled with the desired lightness in weight.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed. 7 These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several views:

Figure l'is a side elevation of my improved crane as attachedto a tractor.

Figure 2 is a rear end view of the crane with Figure 3 is a fragmentary longitudinal section showing the connection of the boom with the wheeled supporting truck.

Figure 4 is a fragmentary side view of a pair of boom legs at their lower end, separated from each other.

Figure 5 is a cross section on line 55 of Fig. 4Q Figure 6 is a sectional plan on line 66 of Fig. 2.

Figure 7 is a similar view on line, 1-1 of Fig. 2. Figure 8 is'a cross section on line 8'8 of Fig. l.

Referringncw more particularly to the char-- acters of reference on the drawings, the crane comprises a long tongue I, upwardly trussed near its rear end so as to avoid possible sagging", and adapted at its forward end for swivel supporting connection with a tractor 2. The tongue at its rear end is rigid with a cross beam 3 at the ends of which are bosses 4 in which are mounted the outwardly projecting spindles 5 of the supporting wheels 6. The above parts form thesupporting base or vehicle of the crane..

The boom of the crane comprises a pair of transversely spaced main rear legs I of tubular form provided at their lower end with depending oriflced plates 8 turnably supported on the spin- ,dles 5 between the bosses and wheels. Secondary tubular and relatively light boom legs 9 project upwardly from legs I in forwardly diverging relation thereto from their lower end.: At'said end, the legs I have flat plates l0 secured on their adjacent faces. adapted to engage, rigid straps ,ll depending from the legs 9 on their opposed The boom legs, which converge toward their upper end in a transverse plane as shown in Fig. 2, are braced intermediate their ends by a horizontal frame I 5 which projects between the front and rear legs and is removably secured in place by U bolts l6 as shown in Fig. 6. At their upper end, the rear legs I are connected by a plate I'I v removablybolted against plates l8 secured on the legs! on their forward face as shown in Fig. 6.

The head of the crane is a unit separate from the boom legs and comprises front and rear sheave blocks 19 and 20 connected by rigid framing 2|. The framing at the bottom and inter- ,mediate the front and rear sheave blocks is provided with a rigid crossbar 22 resting flatly at its ends on thesolid top of the legs 1 and removably secured thereto by bolts 23.

The forward legs at their upper end are provided with upwardly extending straps 24.011 their adjacent faces, which abut against and are removably secured by bolts 25 'to correspondingv straps 26 depending from the sheave block IS on its opposite sides, as shown in Fig. 8. i

The head is thus rigidly but removably tied to the boom legs to ferm the complete boom unit, in which the rear sheave'block 30 is disposed well to the rear of legs 1. i

A cable 28 extends from one drum of a two,-

drum power unit .of conventional type on the tractor over and between certain pulleys of the blocks is and 20 and over those of the hook or lifting block 30 which is disposed below and in vertical alinement with block 20. The winding of this cable on its drum raises the block 30 and any load supported thereby and vice-versa.

Another cable 3] extends from the other drum of the power unit and then over another pulley of block IQ, and then back and forth between said block and an anchor sheave block 32 swivelly mounted on the tongue near its front end. This cable controls theboom and is so arranged that when thecable is wound on the corresponding drum, the boom itself will be raised about the wheel spindles as an axis.

The boom can be swung upwardly from a rearward position at an acute angle to the ground, to

To prevent the boom from tipping forwardly from such position, plates 33 are provided, which depend from the legs I at the front and then rest on the cross beam 3.

From the foregoing description it will be, readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail thepresent and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as deiined'by the a position in which-the rear legs 1 are vertical.

end; the rear legs 'being relatively heavy and plates secured on and depending from said rear legs to form the axial mounting for the boom.

2. In a crane, a boom comprising a head, a pair of rear legs, a pair of front legs, means detachably connecting the head and legs together as a rigid unit, the front and rear legs diverging from their lower end, elements depending from screws insertable through the orifices.

3. In a crane, a boom comprising a head, a pair of rearlegs and a pairof front legs, and means detachably securing the legs and head together as a rigid unit, the front and rear legs diverging upwardly from each other, and the crane head including a framing having a cross bar resting on and detachably secured on the top of the rear legs, and detachable connections between the front legs at the top and the head at its forward end.

4. In a crane, a boom including front and rear pairs of relativelylong legs detachably connected together at their ends, the front legs diverging relative to the rear legs from their lower end and all the legs being spaced apart intermediate their ends, a unitary brace frame fitting between the front and rear legs intermediate their ends and means to detachably clamp the legs and frame together to hold the legs against deviation at the frame.

ROBERT GILMORE LE TOURNEAU. 

